a a 



APPENDIX. 



Since the completion of the ■ Phycologia,' Prof. Agardh 

 has published his new arrangement of Rhodospermeat 



based on a more accurate examination of the conceptacular 

 fruit or "sporiferous nucleus;" and this arrangement, 

 which I should adopt in any New Edition of thai work, 



involves many changes of name, and transposition ot^ place 

 from one family to another. As the old arrangement and 

 names have been preserved in the present compilation, it 

 may be desirable to state the changes made by Ptf 

 Agardh, and adopted by me in my more recent publica- 

 tions, the 'Nereis Borean-Americana, 1 etc. 



The new arrangement of Rhodospermece, so far as the 

 British Flora is concerned, is as follows: — 



Bee. I. DBSMIOSPBRMBjB. Sporifi rous-rmel us consisting of 

 tufted spore-threads attached to <> ccUnla/r placenta. Single- 

 a/ton* formed one in each all of the spore-thready or only in 

 th> U rminal cell, 

 § 1. Nucleus lodged in an external conceptach or capsule, 

 * Placenta basal. Spores pyriform, formed in thi terminal 

 cell of thi spore-threads, 



I. RhodomelacEjE. Frond more or Less articulate, the surface 



involute Tetraspores seriated in the ramuli, or in pod-like 

 receptacles. {Odonthalia, Rhodomela, Chondria, Bostrychia, 

 Rytiphlaxti Polusiphonia, I 1 



II. Laubenciai n. /'.'//'/inarticulate: the surface cells minute, 



Tetraspores scattered through the ramuli irregularly. [Bonne- 

 L'.iLLixnf'ta, Li/mentariOf Champia.) 



